Mechanism for transporting connected steps

ABSTRACT

Three continuous steps (1, 2, 3) of a transportation apparatus, adjoining in front and in rear, are connected to one another by parallel links, thereby forming one step group (123), so that the tread of each step is horizontal at all times. The step group (123), having reached the terminal end of a first stroke track (01), is delivered from the stroke track (01) onto a carriage (7) in engagement with a guide groove (03) as friction wheels (91, 92) rotate. The step group (123) on the carriage (7) is transversely transferred together with the carriage (7) along a circuit which is formed of the guide groove. Then, as friction wheels (93, 94) rotate, the step group (123) on the carriage (7) is delivered to the starting end of a second stroke track (02), and travels in the opposite direction on the stroke track (02). While this is done, the direction of the one step group itself is not changed.

TECHNICAL FIELD

The present invention relates to a continuous transportation apparatus,such as an escalator, moving footway, etc., in which the direction ofits steps themselves cannot be changed when the steps are transverselytransferred after being disengaged from the terminal end of aforward-stroke track and switched to the starting end of abackward-stroke track which extends parallel to the forward-stroketrack, and more particularly, to a continuous transportation apparatusin which a plurality of steps, adjoining one another in front and inrear, are formed into one unit step group by means of a connectingmechanism, and the entire unit step group is transferred and switchedfrom the terminal end of the forward-stroke track to the starting end ofthe backward-stroke track without changing the direction of itself.

BACKGROUND ART

Disclosed in Japanese Patent Applications published as KOKOKU Nos.46-33107, 46-33108 and 46-33109 are continuous transportationapparatuses which are arranged as follows: When one step traveling on afirst stroke track reaches the terminal end of the track, the step isdisengaged from this stroke track and transported toward the startingend of a second stroke track which extends parallel to the first stroketrack. Then, the transferred step is set on the second stroke track, andtravels on the second stroke track in the direction opposite to thedirection of the travel on the first stroke track. These apparatuses aredesigned so that the direction of the step itself cannot be changedduring the travel of the step on the first and second stroke tracks.

As described above, however, all these conventional continuoustransportation apparatuses are constructed in a manner such that stepsare allowed to travel one by one on the stroke track, and the steps atthe terminal end of the first stroke track are transferred one by onefrom this stroke track to the starting end of the second stroke trackvia a curved connecting track.

Incidentally, a large-sized object, such as a wheelchair, cannot becarried by means of only one step, requiring use of a plurality ofcontinuous steps, e.g., three in number, adjoining in front and in rear.In the aforementioned conventional continuous transportationapparatuses, however, each three adjacent steps on the first and secondstroke tracks are oriented oppositely in the vertical direction, withthe result that such a mechanism for loading a wheelchair cannot beincorporated into the above transportation apparatus forinappropriateness in order of step arrangement.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a continuoustransportation apparatus in which an object to be transferred, such as awheelchair, is carried on a unit step group which is formed of aplurality of steps adjoining one another in front and in rear, runs inone direction on a first stroke track is then disengaged from thisstroke track at the terminal end thereof, and further the unit stepgroup is fed transversely, is transferred to a second stroke track whichextends parallel to the first stroke track, and runs on this stroketrack in the direction opposite to the aforesaid direction, in a mannersuch that the order of vertical arrangement of the steps whichconstitute the unit step group is maintained so as not to be changed.

In order to achieve the above object, according to the presentinvention, there is provided a continuous transportation apparatustravelling forward and backward of a type such that a first stroke track(forward-stroke track) and a second stroke track (backward-stroketrack), adapted to travel in opposite directions, are arranged parallelto each other, and the steps are transferred from the stroke track endon the one side to the track end on the other side without changing thedirection of the steps themselves. In this apparatus, two or more stepsare successively connected by means of a parallel link mechanism to formone unit step group to be transferred, the step at each end of each unitstep group is fitted with a cylindrical surface whose center is on thecenter of a pin of its corresponding parallel link and whose radius ishalf the length of the link, the cylindrical surface serving as acontact surface between the unit step groups, each step is provided witha pair of wheels so that each step is set on the track. Also, theapparatus comprises a guide groove for guiding tread leveling rollersattached to at least one step of each unit, a mechanism forintermittently circulating a plurality of moving rail carriages capableof carrying the unit step groups by parallel movement in a rectangularparallelepiped region adjacent to the respective ends of theforward-stroke track and the backward-stroke track, a mechanism forquickly feeding the unit step groups to tile moving rail carriages at acontrolled speed, thereby loading the carriages, and a mechanism forquickly transversely feeding the moving rail carriages at a controlledspeed, then disengaging the unit step groups from the carriages at acontrolled speed, and causing the steps to catch up with and be pressedagainst ones which precede them.

According to the present invention, as described above, only a simplemechanism attached to each step enables a plurality of steps to betransferred from one stroke track to the other stroke track withoutchanging the direction of the steps themselves and the order of thecomposite step groups. Even though the traveling direction is changed,therefore, the direction of the step groups themselves and the order ofthe composite step groups can be prevented from being changed duringthis process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a unit step group which constitutes acontinuous transportation apparatus according to one embodiment of thepresent invention;

FIGS. 2(a) and 2(b) show a switch associated section which constitutesthe continuous transportation apparatus, in which FIG. 2(a) is a planview of this section and FIG. 2(b) is a diagram for illustrating theoperation of the unit step group in the switch associated section;

FIG. 3 is a front view of a carriage loaded with the unit step group ofFIG. 1;

FIG. 4 is a side view of the carriage;

FIGS. 5(a) and 5(b) are views showing a caster of the carriage of FIG.3, in which FIG. 5(a) is a front view and FIG. 5(b) is a side view;

FIGS. 6(a) and 6(b) are views showing a triple roller chain used in theswitch associated section of FIG. 2, in which FIG. 6(a) is a side viewand FIG. 6(b) is a plan view taken along line VIB--VIB of FIG. 6(a).

FIG. 7 is a plan view of a dual-pin-drive Malta-cross mechanism;

FIG. 8 is a plan view of a vertical-type switch associated sectionaccording to an embodiment different from the embodiment of the switchassociated section of FIG. 2; and

FIG. 9 is a front view of the switch associated section of FIG. 8.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is a description of an escalator, as an embodiment of acontinuous transportation apparatus according to the present invention,which uses three adjacent wide steps to transport a wheelchair.

FIG. 1 is a side view showing an example of a unit step group 123traveling on an ascending forward-stroke track 01. This unit step group123 is composed of three steps in total and connecting means formed ofparallel links connecting them, the steps including one step 2 and steps3 and 1 in front and in rear, respectively, of the step 2 as viewed inthe traveling direction thereof.

The steps 1 and 2 are pinned to parallel links which are composed of anupper link 412 and a lower link 512. A distance L between centers of twopins which penetrate the upper link 412 (distance between centers O₄₁and O₄₂) is equal to a distance between centers of two pins whichpenetrate the lower link 512 (distance between centers O₅₁ and O₅₂)(=L). Moreover, the rear end of the upper link 412 integrally forms anarcuate abutting portion 410 whose outer surface is an arcuate surfacehaving its center on the center O₄₁ and a radius of (L/2-P) (where P isa positive or negative value including zero whose absolute value issmaller than L/2).

Also, the steps 2 and 3 are pinned to parallel links which are composedof an upper link 423 and a lower link 523. A distance between centers oftwo pins which penetrate the upper link 423 (distance between centersO₄₂ and O₄₃) is equal to a distance between centers of two pins whichpenetrate the lower link 523 (distance between centers O₅₂ and O₅₃), andboth these values are equal to the aforesaid value L. Moreover, thefront end of the upper link 423 integrally forms an arcuate abuttingportion 430 whose outer surface is an arcuate surface having its centeron the center O₄₃ and a radius of (L/2+P).

As described above, three steps 1, 2 and 3, adjoining one another infront and in rear, are connected to one another into one unit step group123 by means of the two sets of parallel links. The step unit group 123on a stroke track is arranged so that its front arcuate abutting portion430 is in contact with the rear arcuate abutting portion 410 of anotherunit step group 123 traveling ahead, and that its rear arcuate abuttingportion 410 is in contact with the front arcuate abutting portion 430 ofanother unit step group 123 traveling behind. When a plurality of unitstep groups 123 are arranged in a straight line on the stroke track, thedistance between the center O₄₁ of a preceding step group 123 and thecenter O₄₃ of the immediately succeeding step group 123 is[L/2-P]+[L/2+P]=L, which is equal to the distance between centers of thetwo pins penetrating the upper link 412 which constitutes the parallellinks (distance between the centers O₄₁ and O₄₂) and to the distancebetween centers of the two pins penetrating the upper link 423 (distancebetween the centers O₄₂ and O₄₃). It should be noted, however, that thevalue P is zero (P=0) in the present embodiment.

The circular arc length of the front and rear arcuate abutting portions430 and 410 of each unit step group 123 is adjusted to a length so thatthe contact between the arcuate abutting portions 430 and 410 can bemaintained even though the unit step group 123 just ahead of or behind acertain unit step group 123 is bent to a maximum degree with respect tothe latter.

As is also shown in FIG. 3, the steps 1, 2 and 3 which constitute theunit step group 123 are provided with collared wheels 61, 62 and 63,respectively. These wheels 61, 62 and 83 are on the forward-stroke track01 or backward-stroke track 02. The step 2 in the center is providedwith a pair of tread leveling pins 22 on the left and right thereof,individually, with respect to its advancing direction, whereby its tread20 is kept level. As the pins 22 are fitted individually in recessedgrooves 06 which are formed in the forward- and backward-stroke tracks01 and 02, individually, the unit step group 123 can be securely guidedby the stroke tracks 01 and 02. If the tread 20 of the center step 2 iskept level, then the respective treads 20 of the two other steps 1 and3, which are connected with the parallel links, are also kept level bythe parallel links at the same time.

Moving handrails (not shown) are located above and outside the forward-and backward-stroke tracks 01 and 02, and parallel link mechanisms arehoused in spaces under the moving handrails.

The unit step group 123 is driven by a step driving chain 8, i.e., aroller chain traveling outside and over the stroke tracks 01 and 02, asit travels on the stroke tracks 01 and 02 by the collared wheels 61, 62and 63. According to the present embodiment, power is transmitted fromthe driving chain 8 to the unit step group 123 through powertransmission devices, such as a passive medium described in detail in anInternational Application published as No. WO 93/22231. Since what typeof the passive media should be used does not become an issue in thepresent invention, it will be described only in brief herein. Passivemedium holders are attached individually to vertical links 811, 821 and831 stretched between the upper links 412 and 423 and the lower links512 and 513 which constitute the parallel links. The passive mediumholders individually hold passive media 81, 82 and 83 which are formedby lapping a large number of rigid leaves. As the traveling step drivingchain 8 (more specifically, indentations formed on left- and right-handlink plates of the chain 8) engages the upper side of the passive media81, 82 and 83 (rigid leaves) in the passive medium holders, thetraveling power is transmitted from the chain 8 to the unit step group123 through the passive media.

Referring now to FIGS. 2, 3 and 4, an arrangement of a switch mechanismassociated section for disengaging the unit step group 123 from theterminal end of the forward-stroke track 01 and switching it to thestarting end of the backward-stroke track 02 will be described. FIG.2(a) is a plan view of the switch mechanism associated section, and FIG.2(b) is a diagram for illustrating the operation of the unit step group123.

A carriage 7 for carrying the unit step group is used to receive theunit step group 123 disengaged from the terminal end of theforward-stroke track 01 and transfer it to the starting end of thebackward-stroke track 02 without changing the direction of the unit stepgroup 123 itself. In this carriage 7, as shown in the front view of FIG.3 and the side view of FIG. 4, moving rails 73 and 74 are mounted on theupper surface of a flat plate 70 which has lower ribs 71 and 72, and aplurality of casters 75 are mounted on the lower surface of the flatplate 70. When the unit step group 123 is on the carriage 7, the wheels61, 62 and 63 of its individual steps are on the moving rails 73 and 74of the carriage 7, as shown in FIG. 3.

In each caster 75, as shown in the front view of FIG. 5(a) and the sideview of FIG. 5(b), a roller 750 is rotatably supported around ahorizontal shaft 751. Preferably, the roller 750 should be crowned. Asshown in FIG. 5(b), a vertical shaft 753, which supports the horizontalshaft 751 on the flat plate 70 for rotation on a horizontal plane bymeans of a rolling bearing 752, is not positioned right over thehorizontal shaft 751, but is offset for a certain distance with respectto the roller 750. When the carriage 7 moves in a certain direction,therefore, the horizontal shaft 751 never fails to be directed at rightangles to this moving direction, so that the movement of the carriage 7becomes smooth. FIG. 3 is a view showing a situation where the carriage7, which carries thereon the unit step group 123 including the step 2,moves from left to right as illustrated, and FIG. 4 is a view showing asituation where the carriage 7 moves in the direction perpendicular tothe drawing plane.

As shown in FIGS. 3 and 4, guide rollers 76 . . . are mounted on thecentral portion of the carriage 7, in four positions, left, right,front, and rear, around a central axis 0. Under the central portion ofthe carriage 7, moreover, a sprocket 77 is fixed to the lower end of afixed shaft whose axis is in alignment with the central axis 0 in amanner such that it is prohibited from rotating.

On the other hand, a horizontal floor 00 connects with the respectiveends of the forward-stroke track 01 and the backward-stroke track whichextend parallel to each other. As shown in FIG. 2, the horizontal floorhas a guide groove 03 in the form of a circuit with a predeterminedwidth. The center line of the guide groove 03 generates a square whichconnects four points C1, C2, C3 and C4 in FIG. 2.

As shown in FIG. 2, all of the four guide rollers 76 . . . of thecarriage 7 are guided by inside wall surfaces 761 and 762 of the guidegroove 03 when the carriage 7 moves from the point C1 toward the pointC2 or from the point C3 toward the point C4 (or advances in a directionperpendicular to the advancing directions of the stroke tracks 01 and02, that is, moves transversely) or when the carriage 7 moves from thepoint C2 toward the point C3 or from the point C4 toward the point C1(or advances in a direction perpendicular to the direction from C1 toC2).

Moreover, double-row sprockets 04 are arranged individually in positionscorresponding to the four points C1, C2, C3 and C4 in the guide groove03. The double-row sprocket 04 engages with lower rows 052 and 053 of anendless triple roller chain 05, such as the one shown in FIG. 6, so thatthe roller chain 05 is passed around and between the four sprockets 04.Thus, when one of the sprockets 04 is rotated, the roller chain 05travels, so that the remaining three sprockets 04 also rotate.Alternatively, a plurality of sprockets 04 may be rotated synchronously.

An upper row 051 of the triple roller chain 05 engages with the sprocket77 which is attached to the lower central portion of each carriage 7.When the roller chain 05 travels, therefore, the carriage 7 also movesat the same speed. The roller chain 05 is prohibited from beingdisengaged from the sprockets 04 and 77 in a manner such that center-rowrollers 052 of the roller chain 05 are pressed by roller retainers 07which protrude from the inside surfaces 751 and 762 of the guide groove03 in the horizontal floor 00.

Since all the sprockets 04 and 77 which engage the individual rows ofthe triple roller chain 05 have the same shape and size, each carriage 7can change its direction at right angles at the corners (positions ofthe points C1, C2, C3 and C4) of the groove 03. If the carriage 7 lowersits traveling speed when it reaches a position near a corner of thecircuit, it can be fully restrained from going beyond the corner due toinertia from at least one of the four sprockets 04 which are located inthe positions of the corner points C1, C2, C3 and C4. The highest degreeof freedom can be obtained if the speed of the sprocket is controlled bymeans of a control motor which is used in combination with a programcontroller. If one sprocket is driven by using a Malta-cross wheel 09which is driven by means of a dual-pin wheel 08 shown in FIG. 7, 90°nonconstant-speed rotation and 90° pause are repeated mechanically,although the situation of speed change is restricted. If a suitablespeed change gear is used in combination with this, therefore, thesprocket can be driven in a substantially desired state.

If the distance between the forward- and backward-stroke tracks 01 and02 is wide, as in the case where the escalator as the continuoustransportation apparatus according to the embodiment of the presentinvention is provided on either side of a wide staircase for walking, itis necessary only that the distance between the points C1 and C2 of thecircuit be a value obtained by multiplying each stroke of the unit stepgroup carriage 7 by an integer.

As shown in FIG. 2(a), friction transmitting wheels 91, 92; and 93, 94are provided outside the forward-stroke track 01, left and right, nearthe terminal end of the forward-stroke track 01, and outside thebackward-stroke track 02, left and right, near the starting end of thebackward-stroke track 02, respectively. The outer periphery of each ofthese friction transmitting wheels 91, 92, 93, 94 has a V-shapedprofile. As shown in FIG. 3, on the other hand, V-grooves 901 and 902are formed on the left- and right-hand sides, respectively, of each ofthe steps 1, 2 and 3 which constitute the unit step group 123. As therespective outer peripheries of the friction transmitting wheels 91 and92, being rotated at high speed, are forced into the V-grooves 901 and902 in the steps 1, 2 and 3 which constitute the unit step group 123,the unit step group 123, having reached a position near the terminal endof the forward-stroke track 01, is delivered at high speed in itstraveling direction from the forward-stroke track 01, and is quicklytransferred to the carriage 7 which has just reached the point C1. Whenthe carriage 7 is on the point C1, the moving rails 73 and 74 of thecarriage 7 are situated on the extension of the forward-stroke track 01,so that the unit step group 123 travels on the moving rails 73 and 74after traveling on the forward-stroke track 01.

The unit step group 123, having been thus placed on the moving rails 73and 74 of the carriage 7 on the point C1, is transported from the pointC1 to the point C2 as the triple roller chain 05 travels, that is,through the engagement between the sprocket 77 of the carriage 7 and theupper row 051 of the triple roller chain 05. When the carriage 7 reachesthe point C2, the respective outer peripheries of the frictiontransmitting wheels 93 and 94 are forced into the V-grooves 901 and 902in the steps 1, 2 and 3 which constitute the unit step group 123 on thecarriage 7, and the friction transmitting wheels 93 and 94 rotate athigh speed. Thereupon, the unit step group 123 on the moving rails 73and 74 of the carriage 7 is quickly transferred from the position of thepoint C2 to the backward-stroke track 02. Also at this time, thecarriage 7 on the point C2 is situated on the extensions of the movingrails 73 and 74.

The rotating speed of the friction transmitting wheels 91, 92, 93, 94 iscontrolled by means of a control motor. It is advisable to provide thecarriage 7 with wheel stopper means which prevents the unit step group123 on the moving rails 73 and 74 from going too far when the unit stepgroup 123 is to be transferred from the forward-stroke track 01 to themoving rails 73 and 74 on the carriage 7 by driving the frictiontransmitting wheels 91 and 92.

According to the present embodiment, as described above, N number (N=3)of steps 1, 2 and 3 are formed into the unit step group 123, and eachunit step group 123 is switched from the forward-stroke track 01 to themoving rails 73 and 74 on the carriage 7 or from the moving rails 73 and74 on the carriage 7 to the backward-stroke track 02. If the timerequired for the one step 1 which constitutes the unit step group 123 topass over the stroke tracks 01 and 02 is T, a time To required for theunit step group 123 itself to pass over the forward-stroke track 01 isT×N. This indicates that switching of each unit step group 123 must becompleted only within the time To (=T×N).

If the distance between the respective center lines of the forward- andbackward-stroke tracks 01 and 02 is short, a process for delivering oneunit step group 123 from the forward-stroke track 01 to the moving rails73 and 74 on the carriage 7 on the point C1 and a process for deliveringthe immediately preceding unit step group 123 from the moving rails 73and 74 on the carriage 7 on the point C2 to the backward-stroke track 02are executed simultaneously, so that the delivery of the unit stepgroups 123 between the stroke tracks 01 and 02 and the moving rails 73and 74 on the carriages 7 can be carried out without interruption.

Thus, if the delivery of the unit step groups 123 between the forward-and backward-stroke tracks 01 and 02 and the carriages 7 are carried outto advance the processes without interruption while the carriages 7carrying the unit step groups 123 thereon move transversely, in the casewhere the distance between the respective center lines of the stroketracks 01 and 02 is short, the time of transverse movement of the unitstep groups 123 and the time of delivery of the unit step groups 123between the stroke tracks 01 and 02 and the carriages 7 have the samevalue NT/2. Thus, these times are equal to half (To/2) of the time To(=T×N) for the passage of the unit step groups 123 over the stroketracks.

In this case, the standard speed of the escalator is adjusted to 30meters per minute. If the depth and width of the tread of each of thesteps 1, 2 and 3 are 40 cm and 100 cm, respectively, the time T requiredfor each of the steps 1, 2 and 3 to pass over the stroke tracks 01 and02 is

    T=40/(30×100/60)=0.8 sec.

The time (To/2) for the delivery of each unit step group 123, includingthree adjacent steps (N=3) of the same size, between the stroke tracks01 and 02 and the moving rails 73 and 74 of the carriage 7 is

    To/2=T×N/2=1.2 sec.

This time (To/2=1.2 sec) is equal to the time of transverse movement ofthe unit step group 123 on the carriage 7, as mentioned before. Thedistance between the respective center lines of the forward- andbackward-stroke tracks 01 and 02 is expected to range from 1,400 to1,500 mm. As seen from these circumstances, the three steps each havingthe depth of 40 cm must cover a distance of 3×40=120 cm and, at the sametime, achieve a transverse movement of 140 cm or more in 1.2 sec. Inother words, the delivery of the unit step group 123 between the stroketracks 01 and 02 and the moving rails 73 and 74 on the carriage 7 andthe transverse movement of the unit step group 123 on the carriage 7must be executed at a speed of about 1 m per second (60 m per minute).In moving the unit step group 123 between the forward- andbackward-stroke tracks 01 and 02 in one process, therefore, the mass ofthe moving body must be adjusted to as small a value as possible whichis suited for the guide mechanism and speed control. If the distancebetween the respective center lines of the forward- and backward-stroketracks 01 and 02 is long, however, the transverse movement of the unitstep group 123 on the carriage 7 can be executed in a plurality oftransverse movement processes. In this case, the trace of movement ofthe carriage 7 has a transversely elongated rectangular shape.

According to the embodiment described above, the carriage 7 iscirculated along the right-angled tetragon under the floor 00 whichadjoins the respective end portions of the two stroke tracks 01 and 02arranged parallel to each other. Although the floor base for theformation of the circuit need not be deep, in this case, a pretty widefloor space is required for the formation of the circuit. Depending onthe construction of the building, therefore, installation of the circuitof this type may be difficult or impossible.

The plan view of FIG. 8 and the front view of FIG. 9 show an arrangementas a substitute for the aforesaid arrangement, in which a circuit forcirculating the carriage 7 along a right-angled tetragon on a verticalplane is provided at the end portions of the stroke tracks 01 and 02.

Also in this embodiment, a mechanism for moving the carriage along thegroove circuit and a mechanism for delivering the unit step group 123between the stroke tracks 01 and 02 and the moving rails 73 and 74 onthe carriage are basically the same as those of the foregoingembodiment. In the following, therefore, this embodiment will bedescribed only in brief.

According to this embodiment, the circuit is formed in a manner suchthat two carriage guide mechanisms (inside and outside), as structuresin which the center line of a guide groove having a predetermined widthin the vertical and horizontal directions generates a right-angledtetragon on a vertical plane, are opposed to each other across a certainspace in the traveling direction of the stroke tracks 01 and 02. In theplan view of FIG. 8, symbols 7V1 and 7V2 designate the inside andoutside carriage guide mechanisms, respectively, and FIG. 9 shows afront view of the outside carriage guide mechanism 7V2 out of thesemechanisms.

The inside and outside guide mechanisms 7V1 and 7V2 have the sameconstruction. The center line of guide grooves 03V has the shape of aright-angled tetragon, and double-row sprockets 04 . . . are arrangedindividually in positions corresponding to the corners of theright-angled tetragon of each guide groove 03V. Two rows of an endlesstriple roller chain 05 are in engagement with these double-row sprockets04 . . . The guide mechanisms 7V1 and 7V2 themselves are suspended fromthe horizontal floor 100 by means of hangers 7Vll and 7V21,respectively.

Each of carriages 7V to be transferred by means of the aforesaid guidemechanisms 7V1 and 7V2 has horizontal shafts projecting individuallyfrom the front and rear portions of its body in the horizontaldirection, and fixed sprockets 771 and 772 are fixed individually to theextreme ends of the shafts. The one fixed sprocket 771, out of the fixedsprockets 771 and 772 of each carriage 7V, engages one row of the tripleroller chain 05 of the inside guide mechanism 7V1, while the othersprocket 772 engages one row of the triple roller chain 05 of theoutside guide mechanism 7V2. Thus, as the triple roller chains 05travel, the carriages 7V are transferred along the guide grooves 03 ofthe circuit.

Further, each carriage 7V has four horizontal shafts fitted on the frontand rear portions of its body and rotatably supporting guide rollers 76. . . which engage left- and right-hand or upper and lower inside wallsurfaces 761 and 762 of the guide groove 03V.

As shown in FIG. 9, moreover, a circulation-type linear roller guide 7V3is provided in a position under the carriage 7V in transverse movementso that its upper surface is in contact with the lower side face of thebody of the carriage 7V. It bears the weight of the carriage 7V whichcarries the unit step group 123 thereon. This linear guide roller 7V3serves to prevent the carriage 7V being transferred transversely(horizontally) in the circuit from dropping from the guide groove 03V inthe middle. As shown in FIG. 8, the linear roller guide 7V3 is supportedby the support fittings 7V31 which are embedded in the floor.

The above is a description of the first embodiment in which the circuitfor circulating the carriages 7 along the right-angled tetragon on thehorizontal plane is provided at the end portions of the stroke tracks 01and 02, and the second embodiment in which the circuit for circulatingthe carriages 7V along the right-angled tetragon on the vertical planeis provided. These embodiments may be alternatively used inconsideration of the storage space (horizontal-plane space orvertical-plane space). In the case where the forward- andbackward-stroke tracks are on ascending and descending slopes,respectively, the circuits according to the first and second embodimentscan be used as a downstairs circuit (at the starting end of theforward-stroke track or the terminal end of the backward-stroke track)and an upstairs circuit (at the terminal end of the forward-stroke trackor the starting end of the backward-stroke track), respectively.

The unit step group 123 is provided with the parallel links on eitherside, whereby the treads of a plurality of steps which constitute thegroup can be kept horizontal. If the width of steps is narrow, however,the parallel links may be arranged only on one side. According to thepresent embodiment, moreover, the unit step group is composed of threesteps. Alternatively, however, the unit step group 123 may be composedof two steps.

According to the present invention, the switching from one stroke trackto another stroke track can be executed without changing the directionof the steps themselves by silent reliable operation only using a simplemechanism attached to each step.

I claim:
 1. A continuous transport apparatus, comprising:a plurality ofunit step groups, each unit step group formed of a plurality of stepsand having a front and a rear; connecting mechanisms for connecting theplurality of steps in the unit step group; a first stroke track having aterminal end; first unit step running means for transferring unit stepgroups on the first stroke track such that the rear of each unit stepgroup is in contact with the front of another unit step group and thefront of each unit step group is in contact the rear of another unitstep group; a second stroke track aligned parallel to the first stroketrack and having a starting end; second unit step running means fortransferring unit step groups on the second stroke track such that therear of each unit step group is in contact with the front of anotherunit step group and the front of each unit step group is in contact therear of another unit step group, the unit step groups being transferredon the first and second stroke tracks while being oriented to extend ina first direction, parallel to the first and second stroke tracks; acircuit forming a looped connection between the terminal end of thefirst stroke track and the starting end of the second stroke track; acarriage for transporting one unit step group of the plurality of unitstep groups, on the circuit from the terminal end of the first stroketrack to the starting end of the second stroke track, the carriage beingoriented to extend in a second direction; carriage driving means forcirculating the carriage through the looped connection of the circuitwhile maintaining the orientation of the carriage in the seconddirection; and unit step delivery means for delivering the unit stepgroup from the terminal end of the first stroke track to the carriageand from the carriage to the starting the end of the second stroketrack, the unit step delivery means delivering the unit step group whilemaintaining the orientation of the unit step group in the firstdirection.
 2. A continuous transportation apparatus according to claim1, whereinthe connecting mechanism is formed of parallel links, each ofsaid parallel links having front and rear abutting surfaces, and eachstep has wheels which ride on the first and second stroke tracks suchthat, when transferred by the first and second unit step running means,the rear abutting surface of each unit step group is in contact with thefront abutting surface of another unit step group and the front abuttingsurface of each unit step group is in contact with the rear abuttingsurface of another unit step group.
 3. A continuous transportationapparatus according to claim 2, whereineach step is supported by theparallel links with a pin, the step toward the front of each unit stepgroup being supported by a front pin and the step toward the rear ofeach unit step group being supported by a rear pin, the front and rearabutting surfaces of said parallel links are arcuate surfaces around,and at radii from, axes defined respectively by the front and rear pins,and for each unit step group, the sum of the radii for the arcuatesurfaces of said front and rear abutting surfaces is equal to thedistance between the pins supporting steps which are adjacent in theunit step group.
 4. A continuous transportation apparatus according toclaim 1, wherein the continuous transport apparatus is positionedbetween two horizontal floors and said circuit is defined by a guidegroove having a center line and a predetermined width, in one of thehorizontal floors so that the center line of the guide groove forms aright-angled tetragon.
 5. A continuous transportation apparatusaccording to claim 1, wherein the continuous transport apparatus ispositioned between two horizontal floors and said circuit is defined bya guide groove having a center line and a predetermined width, the guidegroove being oriented in a vertical direction so that the center line ofthe guide groove forms a right-angled tetragon in a vertical plane.
 6. Acontinuous transportation apparatus according to claim 1, wherein saidcarriage driving means for circulating the carriage includes a mechanismfor intermittently moving the carriage a unit distance, then pausingbefore again moving the carriage.
 7. A continuous transportationapparatus according to claim 6, wherein the length of a transverse sideof said right-angled tetragon is equal to the distance between theterminal end of said first stroke track and the starting end of saidsecond stroke track, and is a value obtained by multiplying said unitdistance for moving the carriage in the circuit, by an integer.
 8. Acontinuous transportation apparatus according to claim 4, whereinsaidcarriage driving means for circulating the carriage includes foursprockets with one sprocket being provided at each of the corners ofsaid right-angled tetragon of the circuit, a chain engaged with andconnecting each of the four sprockets and a rotating power supplyadapted to move the chain in a fixed direction between the sprockets bysupplying rotating power to at least one of the sprockets, the guidegroove has side walls, the carriage has a guide sprocket surrounded byguide rollers, and the guide sprocket engages the chain and the guiderollers engage the side walls so that the chain moves the carriage andthe side walls guide the carriage through the circuit.
 9. A continuoustransportation apparatus according to claim 5, whereinsaid carriagedriving means for circulating the carriage includes four sprockets withone sprocket being provided at each of the corners of said right-angledtetragon of the circuit, a chain engaged with and connecting each of thefour sprockets and a rotating power supply adapted to move the chain ina fixed direction between the sprockets by supplying rotating power toat least one of the sprockets, the guide groove has side walls, thecarriage has a guide sprocket surrounded by guide rollers, and the guidesprocket engages the chain and the guide rollers engage the side wallsso that the chain moves the carriage and the side walls guide thecarriage through the circuit.